:root{
    --white:#e9e9e8;
    --gray:#333;
    --blue:#0367a6;
    --lightblue:#008997;
/* 背景颜色 */
    --button-radius:0.7rem;
    --max-width:758px;
    --max-height:420px;
/* 外边缘圆角 */
    font-size: 16px;
    font-family: Georgia, 'Times New Roman', Times, serif;
    /* 字体样式 */
}
/* :root根伪类   --为自定义CSS属性，方便重复使用，自定义属性可以使用var（）进行使用 */

body{
    align-items: center;
    background-color: var(--white);
    background: url(/static/img/wallhaven-k9e8ym.jpg);
    background-attachment: fixed;
    /* background-attachment设置背景图像是否固定或者随着页面的其余部分滚动。 */
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
    /* 填充 */
    display: grid;
    height: 100vh;
    place-items: center;
}
.from_title{
    font-weight: 300;
    margin: 30;
    margin-bottom: 1.25rem;
}

.link{
    color:var(--gray);
    font-size: 0.9rem;
    margin: 1.5rem 0;
    text-decoration: none;
}

.container{
    background-color: var(--white);
    border-radius: var(--button-radius);
    box-shadow: 0 0.9rem 1.7rem rgba(0, 0, 0.25);
    height: var(--max-height);
    max-width: var(--max-width);
    overflow: hidden;
    /* overflow 属性规定当内容溢出元素框时发生的事情。 */
    position: relative;
    width: 100%;

}

.container_from{
    height: 100%;
    position: absolute;
    top: 0;
    transition: all 0.6s ease-in-out;
}

.container--signin{
    left: 0;
    width: 50%;
    z-index: 2;

}
.container.right-panel-active .container--signin{
    transform: translateX(100%);

}

.container--signup{
    left: 0;
    opacity: 0;
    width: 50%;
    z-index: 1;
}
.container.right-panel-active .container--signup{
    animation: show 0.6s;
    opacity: 1;
    transform: translateX(100%);
    z-index: 5;
}  
.container_overlay{
    height: 100%;
    left: 50%;
    overflow: hidden;
    position: absolute;
    top: 0;
    transition: transform 0.6s ease-in-out;
    width: 50%;
    z-index: 100;

}

.container.right-panel-active .container_overlay{
    transform: translateX(-100%);

}

.overlay{
    background-color: var(--lightblue);
    background: url(static/img/wallhaven-k9e8ym.jpg);
    background-attachment: fixed;
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
    height: 100%;
    left: -100%;
    position: relative;
    transform: translateX(0);
    transition: transform 0.6s ease-in-out;
    width: 200%;
}
.container.right-panel-active .overlay{
    transform: translateX(50%);
}
.overlay_panel{
    align-items: center;
    display: flex;
    flex-direction: column;
    height: 100%;
    justify-content: center;
    position: absolute;
    text-align: center;
    top: 0;
    transform: translateX(0);
    transition: transform 0.6s ease-in-out;
    width: 50%;
}

.overlay--left{
    transform: translateX(-20%);
}

.container.right-panel-active .overlay--left{
    transform: translateX(0);
}

.overlay--right{
    right: 0;
    transform: translateX(0);
}
.container.right-panel-active .overlay--right{
    transform: translateX(20%);
}
.btn{
    background-color: var(--blue);
    background-image: linear-gradient(90deg,var(--blue) 0%,var(--lightblue)74%);
    border-radius: 20px;
    border: 1px solid var(--blue);
    color: var(--white);
    cursor: pointer;
    font-size: 0.8rem;
    font-weight: bold;
    letter-spacing: 0.1rem;
    padding: 0.9rem 4rem;
    text-transform: uppercase;
    /*  */
    transition: transform 80ms ease-in;
}

.from>.btn{
    margin-top: 1.5rem;

}

.btn:active{
    transform: scale(0.95);
}
.btn:focus{
    outline: none;
}

.from{
    background-color: var(--white);
    display: flex;
    align-items: center;
    flex-direction: column;
    /*  */
    padding: 0 3rem;
    height: 100%;
    text-align: center;
}

.input{
    background-color: #fff;
    border: none;
    padding:0.9rem 0.9rem;
    margin: 0.5rem 0;
    width: 100%;
}

@keyframes show{
    0%,
    49.99%{
        opacity: 0;
        z-index: 1;
    }
    50%,
    100%{
        opacity: 1;
        z-index: 5;
    }
}